This is from Arrigo Boito's opera Mefistofele. Mephistopheles has shown up in Heaven to make trouble. He sings the following lines:
Perdona se il mio gergo
Si lascia un po' da tergo
Le supreme teodie del paradiso . . .
Pardon (me) if my jargon
leaves itself(?) a little behind(?)
the supreme songs of praise of Paradise . . .
I'm confused by si lascia and da tergo, which I think are being used idiomatically here. Can anyone enlighten me?
Because of that, I'm not sure I've grasped the sense. "Pardon me if my jargon is out of date"? "Pardon me if I can't speak as well as the angels"?
Any help is appreciated.